1. Field of the Invention
The present invention relates to a multiplex system for sub-channels which have various priority levels, the multiplex system utilizing a first main transmission channel for transmitting or not transmitting the information signals coming from said sub-channels depending on the priority levels of the sub-channels.
This type of system is applicable to data transmissions which use a main transmission channel of the type defined by Recommendation X28 of the CCITT.
2. Description of the Related Art
For a better utilization of the multiplex system, priority levels are assigned to the sub-channels to be multiplexed so that a sub-channel having a high priority may force itself onto the main transmission channel and interrupt the traffic of the sub-channels having a lower priority. In that regard, the reader may be referred to the publication "TP-119002" (INTERNATIONAL TECHNOLOGY DISCLOSURE of the American Government), 25 Nov. 1990.
A problem which may arise with this type of system is the question of accessibility by transmission for a sub-channel that has a priority level comparable to those already occupying the whole, main transmission channel.